The present inventors have developed a rewritable information recording medium for Blu-ray Disc (BD) (hereinafter referred to as BD-RE disc) which can be used as a recording medium for high-vision images. BD-RE disc is an information recording medium of large capacity, such that data of 25 giga bytes (GB) can be recorded in a single layer and data of 50 GB can be recorded in 2 layers. 1× speed of data transfer rate for BD-RE is determined by specifications as 36 mega bits per second (Mbps). The present inventors have developed GeTe—Sb2Te3-based material as a material for a recording layer in BD-RE for use in 1× speed (see, for example, Patent Literature 1).
Subsequently, the present inventors have developed GeTe—Bi2Te3-based material in which Sb2Te3 is replaced with Bi2Te3 since a recording layer in BD-RE disc compatible with 1-2× speed required higher crystallization-ability than that compatible with 1× speed (see, for example, Patent Literature 2 and Non-Patent literature 1).